Sonographic Association of Placenta Accreta Spectrum In Patients of Placenta Previa - A Systematic Review

Aim: To determine the diagnostic accuracy and epidemiology of placenta accreta spectrum (PAS) in patients of placenta previa. Design: Systematic review. Methods: PubMed, Google Scholar, ClinicalTrials.gov and MEDLINE were searched between January1992 and December 2020. Studies on placenta previa complicated by PAS diagnosed in a defined obstetric population. This research was carried out using standard methods and protocols and keeping in view Newcastle-Ottawa scale for observation and assessment of case study along with the difference approved by consensus. The overall diagnostic accuracy of ultrasonographic findings is the main outcome of this study, whereas the prevalence of placenta accreta in patients of placenta previa and its incidence among different countries all over the world is also described. Results: In this review study, about 300 articles were evaluated. More over about 15 prospective and 14 retrospective case studies incorporated for assessment having complication with placenta previa and PAS. According to the meta-analysis, a significant (p<0.001) heterogeneity was found between case research that evaluate PAS prevalence and incidence in the placenta previa cohort. The median prevalence in case of placenta previa along with PAS came out to be 0.113% (IQR 0.048-0.17).Whereas incidence in females having placenta previa along with complication of PAS came out to be 11.3% (IQR 7.3-20.0). The overall median sensitivity of the ultrasound to find cases of placenta accreta spectrum in patients of placenta previa is 83.33 %( IQR 77.0-94.34) and specificity is 95.9 %( IQR 88.0-98.4). Conclusions: The high level of diversity observed in results obtained by diagnostic and qualitative data showed strong emphasis should be made on implementation of standard methods and protocols for assessment and diagnosis of pregnancy complication like placenta previa, its type and PAS. However, transvaginal and transabdominal ultrasound remains the gold standard diagnostic tool for placenta previa and placenta accreta spectrum.